Sea Shadow (IX-529)
 The Sea Shadow in 1999 off San Francisco |
|
| Overview | |
|---|---|
| Order | October 22, 1982 |
| delivery | March 1, 1985 |
| 1. Period of service |
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|
| Removed from ship register | August 22, 2006 |
| Whereabouts | Scrapped in 2012 |
| Technical specifications | |
| displacement |
563 standard bins |
| length |
49.99 m |
| width |
20.73 m |
| Draft |
4.42 m |
| crew |
approx. 10 |
| drive |
diesel-electric, 2 shafts |
| speed |
14 knots |
The Sea Shadow (IX-529) was a test ship that the United States Navy and the Defense Advanced Research Projects Agency (DARPA) had built under the strictest secrecy of Lockheed in the 1980s . She was 50 meters long, unarmed and had a hull with two submerged floats ( SWATH ). Due to its angular shape, it was barely visible to radar and is considered the first real stealth ship . It was built and used to research techniques for signal reduction and automation. Experience and knowledge gained on the Sea Shadow flowed into later warship classes of the US Navy.
In 1985 the Sea Shadow was delivered to the Navy, but was decommissioned again in 1986. The ship was only shown to the public when it was reactivated in 1993. Between 1994 and 1999 the ship was decommissioned a second time, and in 2006 it was finally taken out of service. The ship was scrapped in 2012.
history
Planning and construction
The Sea Shadow was developed in a joint project between DARPA, the US Navy and Lockheed.
The idea for this came from Ben Rich , then director of the Lockheed Advanced Development Projects Unit (Skunk Works) in 1978. When an employee wanted to take a photo of a model of the Have Blue prototype of the F-117 , the automatic viewfinder did not focus on the aircraft sharp. Rich noted that the camera used an echo sounder-like device to focus and that the shape of the hunter did not reflect the sound waves back to the camera. Skunk Works then built a model of a submarine that was virtually undetectable by active sonar . The Navy, however, was not interested in this idea. Instead, Rich learned of the Navy’s initial tests on ships with two fully submerged floats connected by water (SWATH device carrier SSP Kaimalimo , launched in 1973), so he asked William Perry , Undersecretary of Defense for Research and Technology to enter into a study contract with Skunk Works . This contract, which was ultimately concluded between Lockheed and DARPA, allowed Lockheed to construct the model of a stealth ship. This model was tested on a Soviet X-band radar, as used by the naval reconnaissance and air-launched anti-ship missiles of the Soviet armed forces. Nothing was known about the result of the tests. The Navy finally agreed to the construction of a prototype - but with the proviso that the cost of the Sea Shadow should not jeopardize other projects. This was a new approach for the Navy, as they normally do not build test ships, but instead put the first ship of a class into service and, if it fails, do not allow any further units to follow it.
The Sea Shadow was finally ordered on October 22, 1982. The construction of the ship began in 1983 or 1984, the Navy received the ship on March 1, 1985. The construction costs were about 50 million dollars. The production of the required parts was taken over by several manufacturers, the individual modules were assembled inside the Hughes Mining Barge , a semi-submersible barge that could serve as a dry dock .
Since the Sea Shadow was never put into active service, it was not given the prefix USS , but it is listed on the Naval Vessel Register , the official register of all ships in the US Navy. The classification IX represents Unclassified Miscellaneous Unit to German about: Unclassified other unit .
Rides
The Sea Shadow made its first voyages in 1985 and 1986 under the highest level of secrecy. Therefore, the tests only took place at night in the waters around Santa Cruz Island , California. During the day, the Sea Shadow was inside the Hughes Mining Barge , where it was hidden from view and could be supplied at the same time. These tests were highly successful. Here's how Rich described a typical night:
“One typical night of testing, the Navy sub-hunter airplanes made fiftyseven passes at us and detected the ship only twice - both times at a mile-and-a-half distance, so that we would have shot them down easily long before they spotted us. Several times, we actually provided the exact location to the pilots and they still could not pick us up on their radar. "
“On a typical night of testing, the Navy anti-submarine aircraft made fifty-seven approaches and only spotted the ship twice - both times within a mile and a half, so we could have shot them down before they hit us would have captured. We gave the pilots our exact position several times, and they still couldn't track us with their radar. "
After two years of testing, the Chief of Naval Operations , Adm. James D. Watkins , finally canceled the program in 1986, according to Rich, due to budget cuts in the Navy. It turned out that ship radars, which reproduced the waves on the water surface, clearly showed the outlines of the ship as a "wave-free surface" on the radar screen. To avoid this, the ship would have had to simulate the radar echo of the surrounding waves, but would then have been easily detectable electronically.
Testing did not resume until April 11, 1993. On this day, the Sea Shadow was presented to the public for the first time, and trips were also carried out in daylight. In March 1994, combat group tests with other US Navy warships began off the coast of Southern California. Mainly the electronics were tested, and more and more standard equipment was tested for its military suitability. Tests in San Francisco Bay were completed in late 1994, and the Sea Shadow was relocated to the 32nd Street Pier in San Diego together with the Hughes Mining Barge .
At the beginning of 1999 the Sea Shadow was activated a third time in order to collect data for the development of the destroyers of the Zumwalt class in a test program lasting about six years . She operated from the former Naval Air Station in Alameda . The tests again took place in the waters around San Francisco. The ship was operated the entire time by Lockheed, which worked closely with Naval Sea Systems Command (NAVSEA).
On August 22, 2006, the Sea Shadow was removed from the Naval Vessel Register . The ship was in Suisun Bay , San Francisco . The Navy intended to donate it to an organization that would prepare it as a museum ship and make it accessible to the public. By the end of 2008, the Navy wanted to either hand over the ship together with the Hughes Mining Barge or release it for scrapping. However, since no investor was found, the Navy extended the deadline by another year. A major obstacle to takeover in a ship museum was obviously the financial risk that a potential buyer would have taken. He should have credibly proven to the Navy that he could meet the financial, technical and ecological challenges associated with operating a museum ship. Since no takeover was successful until 2011, the ship was canceled in 2012.
technology
The Sea Shadow was a so-called SWATH ship , which stands for Small Waterplane Area Twin Hull . There was a buoyancy body on both sides of the ship under the water surface. These floats extended over the entire length of the ship of about 50 meters. The width of the Sea Shadow was a good 21 meters, the draft was less than five meters. The displacement was a good 563 tn.l. when fully loaded. , the loading capacity was around 64 tons. The hull was made of carbon fiber reinforced plastic .
A diesel-electric drive with two counter-rotating screws at the ends of the floats propelled the ship. The Sea Shadow was steered by two stabilizers at the stern and two canard- like rudders at the bow of the ship. It could reach speeds of up to 14 knots . The SWATH configuration also allowed operations in conditions up to sea state level 5 (rough seas) , in which the waves can be up to six meters high.
The decor of the Sea Shadow was quite spartan and not designed for long journeys. There were twelve berths on board, otherwise only a microwave oven and refrigerator as well as a table with chairs. While the maximum number of crew members who have ever set sail with the Sea Shadow was 24 men, the standard crew consisted of only eight people. Two teams of four people each worked in six-hour shifts. Three men had fixed tasks on the bridge, while the fourth was available for all tasks that arose elsewhere on board. However, this was not the norm as the bridge was highly automated. All commands, including operating valves or pumping fuel, could be given from there. Similar procedures and methods were adopted in the Smart Ship Project from 1996 .
The Sea Shadow was never intended for active service and was therefore neither armed nor equipped with advanced electronics. Similar to submarines, a navigation radar could be extended from a mast. The Sea Shadow was able to receive and process tactical data from other ships in its combat group. For this purpose, it was equipped with devices based on the Link 11 and Link 16 standards.
Research subject
The Sea Shadow was the first ship in the world that was developed entirely according to the criteria of stealth technology . For this, not only had the radar cross section ( RCS for Radar Cross Section ) are kept as low as possible, the emitted infrared radiation as well as the volume of the power plant had to be minimized. In order to lower the radar cross-section, no 90 ° angles were allowed, in particular the ship's side was not allowed to be at right angles to the surface of the water, as this would generate the so-called broadside flash (German: broadside echo ). The shape of the hull, for example, was based on knowledge Lockheed had gathered when building the F-117 stealth bomber . As a result of the tests with the Sea Shadow , newer classes of ships, starting with the Arleigh Burke class , received no vertical surfaces on the hull, superstructure and masts. Another effect that lowers the RCS is the omission of antennas or weapons protruding from the hull, as well as a railing, which, however, has so far not been possible on series ships. The screws and the transitions of the pontoons were specially designed to leave no detectable wake . The diesel-electric propulsion system should make detection by passive sonar more difficult.
In addition to the stealth measures, the Zumwalt class also benefited from the test results of the automation. The destroyers were originally only planned with a crew of 140, instead of more than 300 men on ships of comparable size. The San Antonio class also benefited from the research.
The control systems tested on board the Sea Shadow were used in the latest generation of operational SWATH ships of the US Navy, the reconnaissance units of the Victorious- class and the Impeccable- class .
Others
John Douglas Charlton, a retired Lockheed engineer, was arrested in 1995 for selling, among other things, secret papers about the Sea Shadow to an FBI agent disguised as a French government official . He was sentenced to two years in federal prison after pleading guilty.
The Sea Shadow was the inspiration for the stealth ship in the James Bond film Tomorrow Never Dies .
literature
- Ben R. Rich and Leo Janos: Skunk Works. Little, Brown and Company, Boston, ISBN 0-316-74330-5 .
Web links
- Navy fact file ( Memento from February 6, 2007 in the Internet Archive )
- Detailed history on the DARPA website (English; PDF file; 28 kB)
- Navy News article from 2003 (Engl.)
- Sea Shadow to globalsecurity.org (Engl.)
Individual evidence
- ↑ Rich et al. 1994, p. 274
- ↑ Entry in the NVR ( Memento of the original from October 21, 2004 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. (engl.)
- ↑ SPIEGEL-online: US-MARINE - stealth ship to be given away. Retrieved on February 25, 2009
- ↑ Fox News: Navy Plans to Scrap First Experimental Stealth Ship (Engl.)
